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(11) | EP 0 433 919 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Device for manufacturing an automotive tire bead |
| (57) A device (1) for manufacturing a tire bead (2) consisting of an annular element (3)
formed from a first metal wire (4) wound in such a manner as to form a number of coils
packed by a second wire (6) wound about the annular element (3) and having its opposite
ends (7) tied in a knot (8). An annular madrel (9) on the device (1) defines a first
annular duct (38) for forming the annular element (3), and a second duct (39) coiled
about the first duct (38). The mandrel (9) is connected to a pneumatic knotting machine
(10) having an input duct (62) and an output duct (63) defining the two halves of
a flat knot (64) and communicating respectively with the inlet (46) and outlet (47)
of the second duct (39). |
[0002] In particular, the present invention relates to a device for manufacturing a bead as described and claimed in Italian copending Patent application n. 68168-A/89, the content of which is incorporated fully herein, and which relates to an automotive tire bead consisting of a substantially circular-section annular element formed from a first wire, generally a continuous metal cable, wound in such a manner as to form a number of packed coils. Said coils are arranged over the substantially circular section of said annular element according to a given law, and are held together by a second non-metal wire or yarn of heat-shrinkable material coiled about said annular element and the opposite ends of which are knotted together.
[0003] It is an object of the present invention to provide a device enabling straightforward, fast, fully automatic manufacture of the above bead.
[0004] According to the present invention, there is provided a device for manufacturing an automotive tire bead comprising an annular element consisting of a number of coils formed from a first bare metal wire; and a second non-metal wire coiled about said annular element and the opposite ends of which are tied in a knot; said device being characterized by comprising an annular mandrel defining a first annular duct for forming said annular element, and a second duct having an inlet and an outlet and wound about said first duct; and a pneumatic knotting machine connected to said mandrel and having an input and output duct interlaced so as to define the two portions of a flat knot; said input and output ducts communicating respectively with said inlet and said outlet of said second duct.
[0005] The invention will now be described by way of example with reference to the accompanying drawings, in which: FIGURE 1 shows a view in perspective of a preferred embodiment of the device according to the present invention;
[0010] Number 1 in FIGURES 1 to 6 indicates a device for manufacturing an automotive tire bead 2 (FIGURE 7).
[0011] As shown in FIGURE 7, said bead 2 is a "program" bead as described in Italian Patent Application n. 68168-A/89 filed concurrently with the present Application and the content of which is fully incorporated herein.
[0012] Said bead 2 consists of a substantially circular-section annular element 3 formed from a continuous bare metal wire 4 wound in such a manner as to form a number of packed coils 5.
[0013] Said coils 5 are held together by a portion of outer non-metal wire or yarn 6 of heat-shrinkable material, e.g. polyamide, wound about annular element 3 and the opposite ends 7 of which are tied in a flat knot 8.
[0014] As shown in FIGURES 1 to 6, device 1 comprises a mandrel 9 for forming bead 2; and a pneumatic knotting machine 10 connected to mandrel 9 for automatically tying knot 8.
[0015] As shown, particularly in FIGURE 3, mandrel 9 comprises an inner ring 11, and an outer ring 12 connected to knotting machine 10. Inner ring 11 is of substantially rectangular section, and is defined by a cylindrical outer surface 13, the opposite axial ends of which blend with two lateral annular surfaces 14 via two opposed truncated-cone surfaces 15. Outer ring 12 is also of rectangular section, and defined by a cylindrical outer surface 16, and a cylindrical inner surface 17 (FIGURE 1) coaxial with surface 16 and having an annular cavity 18 engaged by a peripheral outer portion of inner ring 11, and having an inner surface mating with the outer surface of said inner ring 11.
[0016] Inner ring 11 consists of two coaxial annular bodies 19 and 20 arranged laterally contacting each other along respective annular mating surfaces 21 and 22, each comprising an outer annular portion 23 extending perpendicular to the axis of mandrel 9 from the center line of surface 13, an inner annular portion 24 parallel to but offset axially in relation to portion 23, and an intermediate, truncated-cone, centering portion 25 blending portions 23 and 24.
[0017] As shown in FIGURES 4 to 6, annular bodies 19 and 20 present respective numbers of axial through holes 26 and 27 equally spaced about inner ring 11. In particular, each hole 26 is coaxial with a respective hole 27, and each pair of coaxial holes 26 and 27 houses a respective pin 28. Each pin 28 is force fitted inside respective hole 27, and engages respective hole 26 in sliding manner so as to enable mutual axial displacement of annular bodies 19 and 20, while at the same time ensuring said annular bodies 19 and 20, when mated, are secured angularly integral with each other.
[0018] As shown in FIGURE 3, surface 13 presents an annular groove 29 of substantially semicircular section, the diametrical plane of which coincides with the plane of annular portions 23. In other words, a first transverse half of groove 29 is formed on annular body 19, the second half of which is formed on annular body 20.
[0019] As in the case of ring 11, outer ring 12 also consists of two coaxial annular bodies 30 and 31 arranged laterally contacting in each other along respective annular surfaces 32 and 32 extending perpendicular to the center line of surfaces 16 and 17.
[0020] As shown in FIGURES 4 to 6, annular bodies 30 and 31 present respective numbers of axial through holes 34 equally spaced about outer ring 12. In particular, each hole 34 is coaxial with a respective internally-threaded hole 35 formed axially through respective adjacent annular body 19, 20, and each pair of coaxial holes 34 and 35 houses a pin 36 having a threaded end screwed inside respective hole 35, and a cylindrical portion engaging respective hole 34 in sliding manner and terminating in an external head 36a.
[0021] Pins 36 enable annular bodies 19 and 20 to support respective annular bodies 30 and 31, and act as a guide enabling axial displacement of each annular body 30, 31 in relation to respective annular body 19, 20. In particular, the length of each pin 36 is such as to enable axial displacement of respective annular body 30, 31 in relation to respective annular body 19, 20 by a distance at least equal to the section radius of grooves 29, and between a first position, wherein each annular body 30, 31 is arranged with the respective portion of annular groove 37 coinciding with the portion of annular groove 29 on respective annular body 19, 20, and a second position, wherein each annular body 30, 31 is arranged with the respective portion of annular groove 37 offset by at least one radius in relation to the portion of annular groove 29 on respective annular body 19, 20.
[0022] With reference to FIGURE 3, the bottom of cavity 18 on outer ring 12 presents an annular groove 37 of substantially semicircular section, the diametrical plane of which coincides with the plane of mated surfaces 32 and 33. In other words, a first transverse half of groove 37 is formed on annular body 30, the second half of which is formed on annular body 31.
[0023] When mated, said grooves 29 and 37 define an annular duct 38 (FIGURE 2) for receiving annular element 3.
[0024] As shown in FIGURE 3, inside mandrel 9 there is formed a second duct 39 coiling about duct 38 and comprising a number of sements 40 formed on annular body 19, a number of segments 41 formed on annular body 20, a number of segments 42 formed on annular body 30, and a number of segments 43 formed on annular body 31. Each of segments 40, 41, 42 and 43 communicates with duct 38 via a respective axial slot 44 (only one of which is shown in FIGURE 3).
[0025] Through surface 16 on outer ring 12, a cavity 45 (FIGURES 2 and 3) is formed symmetrical with annular bodies 30 and 31, i.e. extending partly over annular body 30 and partly over annular body 31. Cavity 45 is of such a depth as to intersect duct 39, which communicates with cavity 45 via at least two holes 46 and 47 (FIGURE 3) in turn communicating respectively with segments 42 and 43 and respectively defining the inlet and outlet of duct 39.
[0026] As shown in FIGURE 2 and FIGURES 4 to 6, cavity 45 is engaged by an appendix 48 on pneumatic knotting machine 10, consisting of two identical parallel plates 49 and 50 normally contacting each other along respective flat surfaces 51 and 52, and engaging respective portions of cavity 45. In the contacting position, plates 49 and 50 define a body 53 defined, on the opposite side to that supporting appendix 48, by two flat lateral surfaces 54 and 55 perpendicular to each other and parallel to the axis of outer ring 12. Surface 54 of body 53 presents a flange 56 consisting of two portions respectively integral with plates 49 and 50, and having, on the opposite side to that facing surface 54, a cylindrical cavity 57 engaged in removable manner by a cylindrical end appendix 58 of an injector 59.
[0027] Plates 49 and 50 are respectively integral with annular bodies 30 and 31, and present, on surfaces 51 and 52, respective grooves 60 and 61 defining, when surfaces 51 and 52 are placed together, an input duct 62 and output duct 63 interlaced in such a manner as to define the two halves of a flat knot 64. In particular, input duct 62 extends from an inlet hole 65, formed centrally on the bottom of cavity 57 on body 53, to an outlet hole 66 opening on to the end of appendix 58 and facing hole 46; whereas output duct 63 extends from an inlet hole 67, opening on to the end of appendix 58 and facing hole 47, to an outlet hole 68 formed centrally on surface 55 of body 53.
[0028] Injector 59 consists of a cylindrical body coaxial with appendix 58 and having an axial through hole 69 facing hole 65 when appendix 58 is engaged inside cavity 57. Inside injector 59, there is formed an annular duct 70 surrounding hole 69 and communicating, on one side, with the mid point of hole 69 via a conical tubular nozzle 71 directed towards appendix 58, and, on the other, with a radial duct 72 constituting the output end portion of a device 73 supplying pressurized fluid, preferably compressed air.
[0029] A grip 74 is connected integral with the end of injector 59 opposite the end supporting appendix 58. Formation of bead 2 using device 1 will be described with reference to FIGURES 4 to 6.
[0030] As shown in FIGURE 4, to begin with, annular bodies 19 and 20 are placed together so as to define inner ring 11 together with respective groove 29. Inner ring 11 is preferably mounted on a rotary support (not shown) designed to turn annular bodies 19 and 20 about their axis, and to axially displace the same in relation to each other and between a first or work position (FIGURE 4) wherein annular surfaces 21 and 22 are arranged contacting each other, and a second or unloading position (FIGURE 6) wherein surfaces 21 and 22 are separated by a distance at least enabling withdrawal of pins 28 from respective holes 26, and the formation, between the outer free ends of pins 28 and annular body 19, of a passage at least equal in width to the section diameter of bead 2.
[0031] Wire 4, normally fed off a reel (not shown), is fed inside groove 29 via a known feed device (not shown) and secured, in any convenient manner, with its end contacting a given point on the surface of groove 29.
[0032] Said feed device (not shown) is normally controlled by a computer (not shown), and moves back and forth, as controlled by said computer and according to a given program, in a direction parallel to the axis of ring 11, so as to form, subsequent to rotation of ring 11 about its axis, coils 5 (FIGURE 4) arranged in layers according to a given sequence, and consequently annular element 3, the circular section of which is housed half inside and half projecting outwards of groove 29.
[0033] Wire 4 is then cut by a known type of cutting device (not shown), and groove 29 closed by outer ring 12. For this purpose, annular bodies 30 and 31, which are initially separated with their outer lateral surfaces contacting heads 36a of pins 36, are brought axially together (FIGURE 5) along pins 36 so as to mate surfaces 32 and 33 and so define groove 37, which, together with groove 29, defines annular duct 38 for annular element 3. At the same time, mating of annular bodies 19 and 20 and annular bodies 30 and 31 as shown in FIGURE 5 results in the formation of helical duct 39, in the mating of plates 49 and 50 along surfaces 51 and 52 thus forming ducts 62 and 63, and in engagement of appendix 58 of injector 59 inside cavity 57.
[0034] Wire 6, which, as explained in more detail later on, is originally arranged with its end portion fully occupying hole 69 on injector 59 and is locked axially in relation to injector 59 by grip 74, is released by grip 74, and compressed air is supplied to injector 59 along duct 72. Via duct 72, compressed air is fed into annular duct 70 and out through nozzle 71 into hole 69, thus drawing wire 6 along input duct 62 on knotting machine 10, duct 39 on mandrel 9, and output duct 63 on knotting machine 10, until end 7 comes out of hole 68.
[0035] At this point, said end 7 is engaged by a grip (not shown); annular bodies 30 and 31 are moved axially outwards in relation to inner ring 11 into the detached position in FIGURE 4, thus detaching plates 49 and 50; grip 74 is closed; injector 59 is detached axially from knotting machine 10 (FIGURE 6) thus drawing wire 6; and, at the same time, said end 7 is drawn outwards by said grip (not shown). The simultaneous actions resulting from detachment of injector 59 from knotting machine 10 and the pull exerted by said grip (not shown) on the end 7 of wire 6 projecting from hole 68 provide for tying knot 8 and so completing bead 2.
[0036] Wire 6 is then cut, by a known cutting device (not shown), at the end of hole 69 facing knotting machine 10, and annular bodies 19 and 20 are moved axially in relation to each other, so as to withdraw pins 28 from holes 27 (FIGURE 6), and until they come to rest on respective annular bodies 30 and 31, thus releasing finished bead 2.
1. A device (1) for manufacturing an automotive tire bead (2) comprising an annular element
(3) consisting of a number of coils (5) formed from a first bare metal wire (4); and
a second non-metal wire (6) coiled about said annular element (3) and the opposite
ends (7) of which are tied in a knot (8); said device being characterized by comprising
an annular mandrel (9) defining a first annular duct (38) for forming said annular
element (3), and a second duct (39) having an inlet (46) and an outlet (47) and wound
about said first duct (38); and a pneumatic knotting machine (10) connected to said
mandrel (9) and having an input and output duct (62, 63) interlaced so as to define
the two portions of a flat knot (64); said input and output ducts (62, 63) communicating
respectively with said inlet (46) and said outlet (47) of said second duct (39).
2. A device as claimed in Claim 1, characterized in that said mandrel (9) presents an
external cavity (45) of such a depth as to intercept said second duct (39) at at least
two points; said second duct (39) communicating, at said two points, with said cavity
(45) via two holes respectively constituting said inlet (46) and said outlet (47)
of said second duct (39); said cavity being engaged by a portion (48) of said knotting
machine (10) bearing the outlet hole (66) of said input duct (62) and the inlet hole
(67) of said output duct (63).
3. A device as claimed in Claim 2, characterized in that it also comprises an injector
(59) having a nozzle (71) for injecting pressurized fluid, and a through hole (69)
for said second wire (6); said through hole (69) communicating at a mid point with
said nozzle (71), and said nozzle (71) being directed towards the outlet end of said
through hole (69).
4. A device as claimed in Claim 3, characterized in that, on said knotting machine, said
output duct (63) presents an outlet hole (68) communicating externally, and said input
duct (62) presents an inlet hole (65) communicating with the outlet end of said through
hole (69) on said injector (59).
5. A device as claimed in Claim 4, characterized in that said mandrel (9) comprises an
inner ring (11) having a first outer annular groove (29); and an outer ring (12) having
a second inner annular groove (37) facing said first annular groove (29) so as to
define with the same said first duct (38).
6. A device as claimed in Claim 5, characterized in that said second duct (39) extends
through said inner ring (11) and said outer ring (12); said cavity (45) being formed
on said outer ring (12).
7. A device as claimed in Claim 5 or 6, characterized in that said inner ring (11) comprises
two first parallel coaxial annular bodies (19, 20), each bearing a respective portion
of said first annular groove (29), and designed to move axially in relation to each
other between a first position, wherein said two first annular bodies (19, 20) are
arranged contacting each other so as to define said first annular groove (29), and
a second position, wherein said two first annular bodies (19, 20) are separated so
as to define a passage at least equal in width to the thickness of said bead (2).
8. A device as claimed in Claim 7, characterized in that locking means (28) are provided
between said two first annular bodies (19, 20) for angularly locking the same in said
first position.
9. A device as claimed in Claim 7 or 8, characterized in that said outer ring (12) comprises
two second annular bodies (30, 31) parallel to each other and coaxial with said first
annular bodies (19, 20); each said second annular body (30, 31) bearing a respective
portion of said second annular groove (37) and being connected to a respective said
first annular body (19) (20) so as to move axially in relation to the same between
a third and fourth position, wherein each said second annular body (30) (31) is so
arranged as to present said respective portion of said second annular groove (37)
coinciding with, and respectively offset by at least one radius in relation to, said
portion of said first annular groove (29) on said respective first annular body (19)(20).
10. A device as claimed in claim 9, characterized in that said mandrel (9) also comprises
guide means on each said first annular body (19)(20) for axially guiding said respective
second annular body (30)(31) between said third and fourth positions.
11. A device as claimed in Claim 10, characterized in that said guide means comprise a
number of axial through holes (34) formed through each said second annular body (30)(31),
and a number of axial pins (36) carried on each said first annular body (19)(20) and
each extending in sliding manner through a respective said axial through hole (34);
each said pin (36) having a head (36a) designed to cooperate with and lock said respective
second annular body (30)(31) in said fourth position.
12. A device as claimed in any one of the foregoing Claims from 9 to 11, characterized
in that said cavity (45) is formed partly on each of said two second annular bodies
(30, 31); said pneumatic knotting machine (10) comprising two plates (49, 50) engaging
a respective portion of said cavity (45) and each integral with a respective said
second annular body (30, 31) so as to move with the same between a mated position,
wherein said two plates (49, 50) contact each other along respective lateral surfaces
(51, 52), and a detached position.
13. A device as claimed in Claim 12, characterized in that each said plate (49, 50) presents,
on said respective lateral surface (51, 52), a groove (60, 61) defining, together
with the other said groove (61, 60), said input duct (62) and said output duct (63).